Efficient Group Signatures without Trapdoors.
Giuseppe Ateniese, Breno de Medeiros · 2002
Group signature schemes enable unlinkably anonymous... This paper introduces the first group signature scheme with constant-size parameters that does not require any group member, including group managers, to know trapdoor secrets. This novel type of group signature scheme allows public parameters to be shared among organizations, and are useful when several distinct groups must interact and exchange information about individuals while protecting their privacy.